This is the renewal application for RO1 CA109232 Regulation of the KSHV LANA promoter. It responds to PA PA-07-455 Research on Malignancies in the Context of HIV/AIDS Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8) is convincingly associated with Kaposi's Sarcoma (KS), an endothelial cell tumor and B-cell lymphoproliferative disease such as PEL in AIDS patients. During latency in KS and B-cell tumors fewer than 5% of KSHV genes are transcribed and these genes are implicated in KSHV episome maintenance and oncogenesis. Our prior real-time QPCR array analysis showed that every KS tumor expressed the viral latent genes and viral microRNAs. In addition a variable fraction also expressed viral lytic genes. Hence the question emerges what regulates KSHV latent genes? Our preliminary data suggest that understanding the latent/lytic switch in KSHV will have a significant impact on KS diagnosis and might uncover novel therapeutic targets to cure latent virus infection. Our new transgenic mouse data demonstrate that this ~1000bp sequence mediated B-cell specific activity of LANAp. We propose to continue our analysis of LANAp, expand the initial grant to in vivo analysis of the B-cell specificity of LANAp, the phenotypic characterization of LANA and KSHV miRNA expression in vivo and the analysis of cellular and viral factors in B cells and appropriate endothelial cell models.